I think we maybe are missing a bigger issue for the OP here.
OP, if you were living in a hell of dieting/restriction before to get down to 138 pounds, which is likely because that weight for any male (unless you’re particularly short) is very low, then your depression was most likely largely a result of the restriction and insufficient intake of cals, fats, salt, and other delicious things that are demonized by dr. oz. And your fears about gaining forever endlessly sound very eating disordered. You are a 16 year old dude and you should be eating mcdonald’s and pizza. If doing so causes you or your parents anxiety, there is an issue there with the thinking and perspective, and NOT with the number on your bathroom scale (Which I suggest you eliminate from your life anyway.)
Do you have a therapist or counselor? If the weight gain is a healthy one (i.e. your body actually needs it despite what your mind is saying) then I think this is probably the best route to deal, mentally, with the physical changes that are happening.